CVE-2020-28579

published 2020-11-18

CVE-2020-28579: A vulnerability in Trend Micro InterScan Web Security Virtual Appliance 6.5 SP2 could allow an authenticated, remote attacker to send a specially crafted HTTP…

Priority P2 70 high 8.8 CVSS 3.1

AV N AC L PR L UI N S U C H I H A H

A vulnerability in Trend Micro InterScan Web Security Virtual Appliance 6.5 SP2 could allow an authenticated, remote attacker to send a specially crafted HTTP message and achieve remote code execution with elevated privileges.

Affected

2 ranges

Vendor	Product	Version range	Fixed in
trend_micro	trend_micro_interscan_web_security_virtual_appliance	—	—
trendmicro	interscan_web_security_virtual_appliance	—	—

Detection & IOCs extracted from sources · hover to see the quote

url https://<host>:8443/urlf_reclassifyurl.jsp↗

port 8443↗

path /urlf_reclassifyurl.jsp↗

path /uilogonsubmit.jsp↗

path /rest/windows_client_status↗

path /servlet/com.trend.iwss.gui.servlet.ManageVLANSettings↗

filename libuiauutil.so↗

path /usr/iwss/AdminUI/ui_ctl.sh↗

command curl -ski -d 'wherefrom=&wronglogon=no&uid=reports_only_user&passwd= &pwd=Log+On' https:// :8443/uilogonsubmit.jsp↗

command curl -ski --cookie 'JSESSIONID=B3C8680FE9EEE804422FD8813D58496A' -d 'op=send&url=MyUrl&sender_note=MySendNote&mailsubject=MyMailSubject&sender_addr='$(python -c "print 'A'*0x10000") https:// :8443/urlf_reclassifyurl.jsp?CSRFGuardToken=55MYNQKMBK8KC3EB9TXC3FKOQH372OGX↗

• → Monitor for large POST requests to /urlf_reclassifyurl.jsp on port 8443 with an oversized sender_addr parameter (e.g., repeated 'A' characters), indicative of a stack buffer overflow attempt via strcat in MailNotification. ↗
• → Detect POST requests to /rest/windows_client_status on port 8443 with an oversized password parameter, indicative of the unauthenticated stack buffer overflow (CVE-2020-28578) via strcpy in Java_com_trend_iwss_gui_IWSSJNI_DecryptPasswd. ↗
• → Alert on POST requests to /servlet/com.trend.iwss.gui.servlet.ManageVLANSettings on port 8443 containing shell metacharacters in VLAN-related parameters, indicative of command injection via AddVLANItem calling system(). ↗
• → The exploit chain for CVE-2020-28579 requires a valid session (JSESSIONID cookie) and a CSRFGuardToken; correlate authenticated sessions followed immediately by anomalously large POST bodies to /urlf_reclassifyurl.jsp. ↗
• → Successful exploitation results in code execution as the 'iscan' OS account; alert on unexpected processes spawned by the iscan user on IWSVA appliances. ↗

• · Exploitation of CVE-2020-28579 requires authentication; a low-privileged 'reports only' account is sufficient, lowering the bar for attackers with any valid credentials. ↗
• · The vulnerable MailNotification function is in libuiauutil.so; if this shared library is updated or patched, the overflow vector is removed. Verify the library version on deployed appliances. ↗
• · The attack targets Trend Micro IWSVA 6.5 SP2 build 1901 specifically; confirm build number before applying detection rules to avoid false positives on patched builds. ↗

CVSS provenance

nvd v3.1 8.8 HIGH CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd v2.0 6.5 MEDIUM AV:N/AC:L/Au:S/C:P/I:P/A:P

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